An illumination system of the type mentioned in the introduction is known from WO 2007/093433 A1, WO 2005/083512 A2 and WO 2011/157601 A2. For demanding projection tasks it is desirable to be able to influence the illumination light properties over the illumination field in a targeted fashion. With the illumination system of the generic type this is not possible, or is possible only with high outlay.